Rare K and B Decays in a warped extra dimension with custodial protection

By M. Blanke, Andrzej Buras, Bjoern Duling, K. Gemmler, Stefania Gori. 2008

221 citations recorded by the source corpus.

We present a complete study of rare K and B meson decays in a warped extra dimensional model with a custodial protection of (both diagonal and non-diagonal) ZdLiLj couplings, including K+ ? ?+?, KL ? ?0?, KL ? ?0?+??, KL ? ?+??, Bs,d ? ?+??, B ? K?, B ? K*? and B ? Xs,d?. In this model in addition to Standard Model one loop contributions these processes receive tree level contributions from the Z boson and the new heavy electroweak gauge bosons. We analyse all these contributions that turn out to be dominated by tree level Z boson exchanges governed by right-handed couplings to down-type quarks. Imposing all existing constraints from ?F = 2 transitions analysed by us recently and fitting all quark masses and CKM mixing parameters we find that a number of branching ratios for rare K decays can differ significantly from the SM predictions, while the corresponding effects in rare B decays are modest, dominantly due to the custodial protection being more effective in B decays than in K decays. In order to reduce the parameter dependence we study correlations between various observables within the K system, within the B system and in particular between K and B systems, and also between ?F = 2 and ?F = 1 observables. These correlations allow for a clear distinction between this new physics scenario and models with minimal flavour violation or the Littlest Higgs Model with T-parity, and could give an opportunity to future experiments to confirm or rule out the model. We show how our results would change if the custodial protection of ZdLijL couplings was absent. In the case of rare B decays the modifications are spectacular.

Subfields: Artificial Intelligence, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/92dfd01ba9fd3b9cfe722edaa78ea3a2a73030c2

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Citations in the corpus

Anatomy and phenomenology of FCNC and CPV effects in SUSY theories (2009, methodology): “6 with respect to the expected spectrum at the LHC.”
The anatomy of Z′ and Z with flavour changing neutral currents in the flavour precision era (2012, background): “ctations in avour physics and the role of right-handed (RH) currents. In fact certain lessons gained from the involved studies of the LHT model [31,32] and RS scenario with custodial protection (RSc) [33] as summarized in [34] will be seen here in a much simpler setting. In particular our analysis i”
Higgs Physics at the HL-LHC and HE-LHC (2019, methodology): “Integrating out the Kaluza-Klein (KK) modes of mass mKK , and working in the limit of a brane-localised Higgs, keeping only terms of leading order in v(2)/m(2)KK , the SM quark mass matrices are given by [680] (see also [681, 682, 683, 684, 685, 686, 687, 688, 689], and Ref.”
Rare $B$ Decays as Tests of the Standard Model (2016, background): “r-changing Zcouplings can either be generated at the loop level (e.g. in the MSSM [72]) or at tree level (e.g. in models with partial compositeness [73] and the closely related Randall-Sundrum models [74,75]). They generate mostly (C(0) 10 ) ‘ qrather than (C (0) 9 ) ‘ qdue to the accidentally suppr”
Flavor Physics in the Quark Sector (2009, methodology): “However, in this case the stringent constraints from ǫK and ǫ ′ K generically disfavour visible effects in other observables, although it is still possible to have some effect, in particular in the phase of the Bs mixing amplitude [181, 182].”
An explicit Z′-boson explanation of the B → K∗μ+μ− anomaly (2013, background): “1) is highly non-standard, and that the usual suspects — such as the minimal supersymmetric SM [12, 13], warped extra dimension scenarios [14, 15] or models with partial compositeness [16, 17] to just name a few — cannot accommodate the observed deviations (this point has also been stressed in [8, 9”
Electroweak and Flavour Structure of a Warped Extra Dimension with Custodial Protection (2009, methodology): “In order to simplify the phenomenological discussion in [27, 44] we chose to work with the (+− − − −) sign convention for the metric, i.”
Electroweak constraints on flavorful effective theories (2015, background): “A detailed discussion on rare K and B decays in custodial protected models can be found in [61], while a discussion on top flavor violating decays can be found in [62].”
Left-handed Z′ and Z FCNC quark couplings facing new b → sμ+μ− data (2013, background): “ssed in [65] the recent data on these decays could be a support for this model. For a recent discussion in this spirit see [67]. Finally in the Randall-Sundrum model with custodial protection one nds [68] R (B s) = 1:00 0:10; 0:6 r1:35 (62) with equal probability of rbeing suppressed or enhanced wit”
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ΔF = 2 observables and fine-tuning in a warped extra dimension with custodial protection (2008, methodology): “ntribution. Therefore their impact is subleading not only in the case of ∆F = 2 observables, where the Zcontributions are of higher order anyway, but also in the case of ∆F = 1 rare decays studied in [56]. In this context we underline that the custodial protection mechanism for the Zdi L d¯j L coupl”
Higgs-mediated FCNCs: natural flavour conservation vs. minimal flavour violation (2010, background): “This strict correlation of Br(Bs;d ! + ) shown in gure 4 should be contrasted with non-MFV frameworks, such as the MSSM with non-minimal avour structures [ 26, 56] or models with warped space-time geometry [ 66 ].”